Fluid pressure control mechanism



,March 12, 1946. R. R. sTEvENs 2,395,448

FLUID PRESSURE CONTROL MECHANISM original Filed oct. 29,- 1942 2'sheei -.-sneef1v (nimm.

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n w I f Y j l mi il 7/ INVENTOR .INVENroR @i f *ATTORNEY 2 shets-sheei 2 arch 1 2, 1946- R. R. STEVENS FLUID PRESSURE CONTROL MECHANISM original Filed oct. 29, 1942 Patented Mar. 12, 1946 FLUD'- PRESSURE CONTROL MECHANSM Roy E. Stevens, Forest Hills, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Original application October'29, 1942, `Serial No.

463,792, now Patent No. 2,383,278, dated August 21, 1945.

Divided and this application October 2, 1943, Serial No. 504,701

1 Claim. (Cl. 121-41) This invention relates to fluid pressure control mechanism and more particularly to means for remotely controlling the selective positioning of a multi-position device; the present application being a division of my copending application, Serial No. 463,792, filed October 29, 1942, and issued as Patent No. 2,383,278 on August 21, 1945.

In marine craft, such as powered by Diesel engines, a maneuvering gear is usually provided on the engine for controlling same. One type oi gear embodies a multi-position element such as a wheel which is rotatable to different engine controlling positions, including a neutral position in which the engine is stopped. At one side of neutral position is a forward starting position for putting the engine in motion in a direction to cause movement of the craft forwardly, a control zone for varying the amount of fuel supplied to the engine to govern the speed or power output of the engine, and a stop position for cutting off the supply of fuel to the engine for causing same to stop. At the opposite side of neutral position there is another starting position for putting the engine in motion in the reverse direction to cause astern movement of the craft, a control zone for varying the power output or speed of the engine operating in this reversev direction, and an engine stopping position'.

One object of the invention is the provision of a fluid pressure power system for selectively controlling the position of a multi-position device, such as the maneuvering gear just described.

Another object of the invention is the provision of a fluid pressure system providing for selective positioning of a maneuvering gear or the like from a remote control station such as the deck or pilot house of a marine craft.

Another object o f the invention is the provision of a remote control pneumatic power positioning system for a maneuvering gear or the like so constructed as to provide promrt and accurate positioning of the gear in responsev to different selected operations of an operator.

According to the above objects I provide a pneumatic remote control system for selectively causing prompt and accurata` movement of a de-Y vice to be controlled to any selected one of a plurality of positions. This system is associated, for illustrative purposes only, with a maneuvering gear such as above described and embodies a manually operable selector device arranged to be located in the pilot house of a marine craft and connected for remotely controlling aprime mover located at the engine in the craft for controlling the maneuvering gear. associated with said engine, said prime mover being operative in response to manual positioning of said selector device to correspondingly position said maneuvering gear.

Diferent maneuvering gears or other similar devices may have positions which differ in number, function, and disposition from the positions of the specific maneuvering gear above described, but the invention with suitable modioation within its scope is equally applicable to the control of such gears or devices as to the structure used for illustration, as will be readily apparent to those skilled in the art from the description to follow.

Other objects and advantages will be apparent from the following more detailed description of the invention.

In the accompanying drawings, Fig. 1 is a dagrammatic view, partly in section and partly in outline, of the improvedremote control system arranged forcontrolling the maneuvering gear of a marine craft; and Fig. 2 is cross-sectional view of the power means shown in Fig. 1 employed for actuating the maneuvering gear to its different controlling positions.

Description In the drawings the reference numeral l indicates 4a rockable control shaft of a maneuvering 'gean `such as used on marine craft, and the numeral 4 indicates a wheel for turning'sad shaft to different positions to control the starting of an internal combustion engine in either one direction or in the reverse direction, dependent upon vthe desired direction of movement of the craft, and to then control or vary the power output or speed of the engine, and to stop the engine when desired. These different positions may be identicated by a, pointer 3 associated with wheel 4 .and suitable legends applied to a stationary index head 2, as shown in the drawings, it being noted that rotation of the wheel in a clockwise direction 4from Neutral -position is arranged to provide for movement of the craft in an Ahead direction, while rotation in the opposite direction is arranged to provide for Astern movement of the craft. At both of the `opposite sides of NeutralA position there is a Start position for putting the engine in motion in either one direction or the reverse direction, a Full position to obtain maximum engine output, a Slow position to provide for operation of the engine at a ychosen reduced output*` or Yat an idling speed, and a Stop rposition for' stopping theengine. The space between the legends Full and Slow at each side of Neutral position constitutes a zone for obtaining different degrees of engine output or speed between the maximum, and minimum or idling.

The invention comprises remote controlled power means for moving any member such as the wheel 4 and shaft I promptly and with accuracy to any selected one of a plurality of positions such as the positions just described for shaft I and wheel 4. The means controlled by shaft I for controlling the engine are therefore not essential to a clear understanding of the invention, and will not be further discussed.

In practice the wheel 4 and shaft I are mounted directly on the engine to be controlled. According to the invention I provide the Wheel 4 with sprocket teeth and secure directly to the engine and preferably over the wheel 4 a plate or panel for carrying a power means to actuate the sprocket wheel 4 to turn the shaft I to its different positions. A manual selector device 6 is provided for controlling the operation of this power means. The selector device 6 may be located at any suitable station as in the pilot house of the craft and thus remote from the power means and engine to be controlled.

The power means carried by the panel 5 comprises a sprocket wheel 1 which is journaled on a shaft 3 secured to said panel. This sprocket Wheel is preferably identical with the sprocket wheel 4 and is aligned therewith, and the two wheels are connected together by a chain 9 for rotation in unison. A pinion gear I secured to sprocket wheel 1 has driven engagement with a gear sector II which is journaled on a pin I2 secured to the panel 5. Rotation of the sector II in either one direction or in the opposite from a neutral position shown will therefore operate the sprocket wheels 1 and 4 to turn the maneuvering gear shaft l to the different positionsabove described, as will be apparent. A pointer I3 xed against turning to the end of shaft 8 overlies the adjacent portion of gear sector II for registering with lines or legends which may be located on said sector, as shown in Fig. 2, to correspond with the different positions of the maneuvering gear shaft I. The main purpose of pointer I3 is t0 insure that the gear sector II will be in its neutral position shown at the time the chain 9 is applied to the sprocket wheels 4 and I with the wheel 4 in its neutral position shown, so as to insure exact positioning of the maneuvering gear shaft I for different positions of the gear sector II.

For operating the gear sector II, I mount on the panel 5 a pneumatic control motor I5 which comprises a power cylinder I6 containingv a double acting piston I1 having at one side a pressure chamber I8 connected to a passage I9 and having at the opposite side a pressure chamber connected to a passage 2l. The piston I1 has a rod 22 extending centrally from one face through the pressure chamber 20 and through a pressure head 23 closing the outer end of said chamber. A suitable packing 24 is mounted in the head 23 around the rod 22 to prevent leakage of fluid under pressure from the pressure chamber 28 to the atmosphere along said rod. The outer end of the rod 2'2 is pivotally connected by a pin 25 to one end of a link 26 the opposite end of which is adjustably connected by screw threads to one end of a link 21. The opposite end of link 21 is pivotally connected by a pin 28 to the gear sector II. A lock nut 29 screw-threaded on the link 21 is arranged for engagement with the end of link 26 for rigidly securing the two links in an adjusted condltion.

The piston I1 is shown in Fig. 2 in a neutral position for correspondingly positioning the gear sector II, sprocket gears 1 and 4 and thereby the maneuvering gear shaft I. Movement of the piston I1 in cylinder I6 in the direction of the right hand Will operate to turn the gear sector II in a counterclockwise direction, which in turn will rotate the sprocket Wheels 1 and 4 and thus the maneuvering gear shaft I in a clockw,`ise direction to provide for forward movement of the craft, while movement of piston I1 from its neutral position in the opposite direction or toward the left hand will cause movement of the maneuvering gear shaft I in the reverse direction to provide for astern movement of the craft. l

The operation of piston l1 to move the maneuvering gear shaft I to its different positions ls arranged to be effected by a differential in fluid pressures provided in chambers I8 and 20 by a control valve device 32 mounted on one end of the power cylinder I6, said control device being in turn controlled by the cooperative action of the power piston I1 and of a pilot device 33 mounted on top of the power cylinder I6, as will be later described.

' The control valve device 32 comprises a casing containing fluid pressure supply and release valve mechanisms 35 and 36, respectively, arranged to control, through passages I9 and 2|, the supply of iiuid under pressure to and its release from chambers I8 and 20, respectively, at

Iopposite sides of the power piston I1.

Both of the valve mechanisms 35 and 36 may be of identical structure, each comprising a supply valve 31 contained in a chamber 38 which is constantly supplied with fluid at a desired reduced pressure, such as 65 pounds, from any suitable source by way of a pipe 39, a reducing valve device 40 and a pipe 4I. Each supply valve 31 has a fluted stem 42 extending through two suitably aligned bores provided in the casing at opposite sides of a chamber 43, and into a chamber 44 where said stem is connected by a reduced portion 45 to an axially arranged release valve 46. A plunger 41 is slidably mounted in a bore in the casing, the chamber 44 at one side of the plunger constituting one end portion of this bore. Any suitable packing means (not shown) may be provided between plunger 41 and the wall of the bore to minimize leakage of fluid under pressure from chamber 44 past said plunger. The plunger 41 has a valve seat provided for engagement by the release valve 46 to close communication between chamber 44 and a passage 48 extending through the plunger and opening to a chamber 48 at the opposite side of the plunger. .The chamber 49 is in constant communication with the atmosphere. A spring 50 in chamber 44 acts on the plunger 41 to unseat same from the exhaust valve 46, while a spring 5I in chamber 38 acts on the supply valve 31 for seating same.

The valve 31 is arranged to control flow of fluid under pressure from chamber 38 to chamber 43, While valve 46 is arranged to release iiuid under pressure from chamber 43 by way of the uted stem 42 of valve 31 and thence through chamber 44 and past the valve 46 to exhaust passage 48. Chamber 43 in valve device 35 is connected to passage I9 leading to chamber I8 at one side of the power piston I1, while assidus' chamber 43' in valve device 36 is connected to passage 2| leading to chamber 20 at the opposite side of power piston I1.

For controlling operation of the two valve devices 35 and 36 a lever 52 pivoted on a pin 53 in the casing is movable in a direction parallel to the length of the power cylinder I5, and it will be noted that said valve devices are located at the opposite sides of said pin in the direction of the rocking of said lever. Adjacent pivot pin 53 the` lever 52 has an outstanding arm 54 which includes an adjustable pin 55 engaging plunger 41 of the valve device 35. An oppositely eX- tending arm 56 includes an adjustable operating pin 51 which engages plunger 41 of the valve device 36.

With the lever 52 in its neutral position shown, both screws 55 and 51 are adjusted to move the plungers 41 in the respective valve devices 35 and 36 downwardly into seating engagement with the release valves 45 and then a slight further adjustment of both of said screws is effected to open the supply valves 31 to a small degree. Fluid under pressure frorn the supply pipe 4I will then flow past the valves 31 to passages I9 and 2| and thence into chambers I8 and 25, respectively, at opposite sides of the power piston.

The pressure of fluid thus obtained in chamber I8 is effective past the iluted stem 42 of valve 31 in chamber 44 of the valve device 35 wherein it acts on the respective plunger 41 to urge same in a direction to permit seating of the supply valve 31. Likewise, the pressure of fluid in chamber is effective in chamber 44 of the valve device 36 wherein it acts on the respective plunger 41 to urge same in the saine direction, it being noted that the iiuid pressure acting on one plunger 41 opposes that on the other. When the pressure of fluid thus obtained past the supply valves 31 in chambers IS and 2B and acting on plungers 41 is increased to a certa-in degreel a suiicient movement of both of said plungers will occur to permit seating of the supply valves 31 and thus prevent further ow of fluid under pressure to chambers I8 and 25.

In actual practice it has been found that a fluid pressure such as fty pounds in chambers 44 acting on the plungers 41 will create such movement or deformation of said plungers or other parts of the device as to provide for seating of the supply valves 31 if said valves are initially unseated for instance around one thousandth of an inch by adjustment of the screws 55 and 51.

It will be no-ted that the two plungers 41 are opposedly connected through the adjusting screws 55 and 51 and the two arms 54 and 5E, respectively, of the operating lever 52 and that such connections constitute what would commonly be considered rigid connections. The seating of the valves 31 when the plungers 41 are subjected to a certain pressure of fluid in chambers 44 is therefore considered or believed due to the elasticity of the materials in the connections between said plungers and the lever 52, but the elastic limit of said materials is not exceeded so that permanent deformation of any part of the connections does not occur.

From the above description it will be noted that both of the valve devices and 36 operate with lever 52 in its neutral p-osition on what is commonly known as the self-lapping principle but such operation is not dependent upon control springs which have heretofore been considered necessary, as illustrated by way of example in a similar pneumatic control motor disclosed in my Cil copending application No. 432,776, filed February 28, 1942.

With the lever 52 in its neutral position shown.

and chambers VI8 and 20 at opposite sides of the'A power. piston. l1 both charged with iiuid at the same degree of pressure, said piston will be in a static condition and for instance in neutral position as shown in Fig. 2. These same pressuresV acting on the two p-lungers 41 also oppose and'. balance each other and will not therefore oppose initial movement of. the lever 52 out of the neutral position shown.

Now let it be assumed that the lever 52 is rocked in a clockwise direction from neutral position. The operating pins 55 and 51 will move with said lever and allow the pressure of fluid in chamber v44 of the valve device 3B to move the plunger 41 thereof with the pin 51 and thus out of engagement with the respective exhaust valve 46, while in the valve device 35 the operating pin 55 will shift the plunger 41 downwardly to unseat the supply valve 31. As a result of this Operation uid under pressure will be released from chamber 20 to reduce the pressure on one side of the power piston I1 and at the same time fluid under pressure will be supplied from the supply pipe 4I to chamber I8 for increasing the pressure of fluid on the opposite side of the power piston. A differential between 'the fluid pressures at opposite sides of the power piston I1 will be thus created acting in the direction of the right hand which will move said piston in said direction to thereby actuate the gear sector II and sprocket wheels 1 and 4 to turn the maneuvering gear shaft I in a clockwise direction.

In the operation just described it will be noted that a minimum of effort is required to initiate. movement of the lever 52 from its neutral position due to the initial balance of fluid forces on the two plungers 41 as above mentioned, and this provides for quick response of the power piston l1 to operation of the pilot device 33 which will be later described. However after the release` valve 46 in the valve device 3S is opened to reduce the pressure of fluid in the power piston cham-v ber 20 and the supply valve 31 in the valve device 35 is opened to increase the pressure in the power piston chamber I8, the corresponding.reduction in pressure on plunger 41 in the valve device 36 and increase in pressure on plunger 41 in the valve device 35 creates a force which opposes movement ofthe lever 52 and tends to return same to its neutral position. This is not material however since the actuating force applied to the. lever by the pilot device 33, as will be later described, prevents such undesired reverse movement of the lever.

When the maneuvering gear shaft I obtains a desired position under the action of the power piston I 1 it is necessary to Stop movement of this piston and this is obtained, as will be later described, by the cooperative action of said piston and the pilot device 33 to return the lever 52 to its neutral position for again balancing the iiuid pressures on opposite sides of said piston. As the lever 52 is thus returned to neutral position, the upward movement of the adjusting pin 55 will permit seating of the supply valve 31 of the valve device- 35 ,following which the plunger 41 of said device will be moved out of contact with the respectivev release valve 45 by the pressure of fluid in the chamber 44 which pressure will at this instant be in excess of the normal degree of for instance fty pounds. The pressure in the power piston chamber I8 and below the plunger 41 in ther valve device 35 will then reduce past the respective release valve 46 until when the normal degree of fty pounds is obtained the resiliency of the connection between the lever and said plunger will urge said plunger into seating engagement with said release valve and thus bottle the remaining fluid in said chamber. At the same time that this occurs the pin 51 will actuate the valve device 36 to increase the pressure in the power piston chamber 26 to the normal degree of for instance fifty pounds as before described, whereupon the piston I1 will be stopped, subject on opposite sides to fluid pressures of the same degree but less than the pressure of the supply iluid in pipe 4I.

If the lever 52 is again rocked out of neutral position in the direction of the right hand, a differential of pressures will be again created on the power piston to|move same further toward the right-hand and such movement will cease in a position determined by when the lever 52 is returned to neutral position, as will be clear from the above description. It will thus be seen that the piston I1 can be caused to turn the maneuvering gear shaft I in a clockwise direction and to stop said shaft in any position dependent upon.

the return of lever 52 to its neutral position.

Only a certain differential of fluid pressures is required on the power piston I1 to ensure operation thereof to turn the maneuvering gear shaft I, and any greater differential would result not only in waste of fluid under pressure but in an increased degree of time for balancing the opposing fluid pressures on said piston in order to stop movement thereof in a selected position, or in other words, to prevent travel of the piston and thereby of the maneuvering gear shaft past or beyond the selected position.

This limiting of the differential of fluid pressures on the power piston is preferably obtained by restricting the release of fluid under pressure from the one side of the power piston through the release passage 48 with respect to the rate of supply of fluid under pressure to the opposite side. To accomplish this the release passage 48 may be provided with a suitable choke or restriction 48a to provide the desired reduced venting capacity and in the operation above described it will be seen that this restricted release of fluid under pressure from chamber 20 at one side of the power piston acting in conjunction with the displacement of said piston will prevent the pressure in chamber 2!) becoming reduced excessively with respect to increasing pressure in chamber I8 during movement of said piston by fluid pressure in chamber I8. The differential of pressures on the piston will be thus limited so that when the lever 52 is returned to neutral position, a shorter period of time, than otherwise lwould be necessary, will be required to increase the pressure in chamber 20 back to the normal degree for stopping the piston with accuracy in the desired position.

In addition to the above, the limiting of the reduction in pressure in chamber 28 also results in a corresponding limit in the reduction in pressure on plunger 41 of the valve device 36 and hence a like limiting of the dilferential of forces applied to the lever 52 by the two plungers 41, and this is desirable in that after the lever is out or neutral position it minimizes the degree of force which opposes movement of said lever by the pilot device 33 which will be later described.

It will now be seen that clockwise movement of lever 52 from neutral position will cause prompt movement of the power piston toward the right hand and that this movement of said piston will cease in a position determined by the return of lever 52 to neutral position.

If the lever 52 is moved from neutral position in a counterclockwise direction the valve device 36 will be operated to eifect an increase in iluid pressure in chamber 20 and the valve device 35 will at the same time be operated to reduce the pressure in chamber I8 to thereby provide a. differential of fluid pressures on the power piston I1 for moving same in the direction of the left hand to turn the maneuvering gear shaft I in a counterclockwise direction. Return of the lever 52 to neutral position will effect equalization of the pressures on the power piston to stop same. This operation is identical in all respects to that resulting from clockwise movement of the lever 52 from neutral position and subsequent return to neutral position and a further description thereof is therefore not considered necessary.

The pilot device 33 comprises a cylinder 60 containing a double acting piston 6I having at one side a pressure chamber 62 and at the opposite side a pressure chamber 63. The piston 6I comprises a pressure head 64, two oppositely disposed packing cups 65 mounted against opposite faces of said head and clamped thereto by two oppositely arranged pressure plates 66. The pressure chamber 62 is closed by a pressure head 61 through which extends a piston rod 68. A suitable packing 59 is provided in the head 61 for contact with rod 68 to prevent leakage of fluid under pressure from chamber 62 along said rod to the atmosphere. The end of rod 68 in chamber 62 engages one of the pressure plates 66 and said rod is provided with a portion 69 of reduced section which extends through both of the plates 66 and the piston head 6I into pressure chamber 63. A sleeve 10 in chamber 63 is mounted on the reduced portion 69 of the piston rod and urged against the adjacent pressure plate 66 by a nut 1I provided on the end of said reduced portion for securely. clamping the two packing cups 65 to the pressure head 6I.

The portion of chamber 63 adjacent the piston 6I is of the same diameter as chamber 62 for cooperation with said piston, but beyond this portion the chamber 63 is of greater diameter in order to provide two spaced annular shoulders 12 and 13, the shoulder 13 being provided on the end of a cover 14 which closes the left hand end of. chamber 63. A sleeve 15 slidably mounted in the enlarged portion of chamber 63 has substantially midway between its ends an annular outstanding collar 16 arranged to engage shoulder 12 for limiting movement of said sleeve in the direction of the right hand to the position shown, A washer 11 slidably mounted on sleeve 10 ahead of nut 1I is also arranged to'slide in the enlarged portion of chamber 63 and to engage shoulder 13 provided on the end of cover 14 for limiting movement of the washer toward the left hand. Interposed between and bearing against the adjacent faces of washer 11 and collar 16 outside of the sleeve 15 is a coil spring 18 arranged to oppose movement of the washer 11 in the direction of collar 16 and to also oppose movement of said collar and the sleeve 15 in the direction of said washer. Normally, that is, when both chambers 62 and 63 are at atmospheric pressure, the

spring 18 is arranged to hold the washer 11 in contact with shoulder 13 and the annular collar 18 in contact with shoulder 12. Under this condition, one end of sleeve 15 is arranged to engage the adjacent face of the pilot piston 6I forthereby dening and holding the pilot piston 6l in its neutral position shown in Fig. 2.

.A caging element 8l) is slidably mounted in the end of sleeve 15 opposite that engaging piston 6l This element has one or more slots 8| extending lengthwise thereof and the sleeve 15 is provided with a pin 82 which extends into each slot 8| for limiting movement of the element 88 outwardly of the sleeve i5. The outer end of the caging element 80 has an inturned spring seat 83,

A second caging element 84 is slidably mounted on sleeve 10 and freely extends through a suitable opening provided through an annular rib 85 extending inwardly from the sleeve 15. At the end of the caging element 84 adjacent spring seat 83 on the element 30 is an annular outwardly extending spring seat 85. A snap ring 81 is secured in an annular groove adjacent the opposite end of sleeve 94 and at the opposite side of rib 85 for contact with said rib.

Two coil springs 88 and 89 under a chosen degree of pressure and encircling the caging element 84 within the sleeve 15 bear at one end against the rib.85 on said sleeve. The opposite yend of the outer spring 8S bears against the spring seat 83 provided on the caging element 80, While the opposite end of the inner spring 89 bears against spring seat 88 provided on the caging element 84. With the piston 5l in the neutral position shown the outer spring 88 is therefore confined under pressure between the spring seat 83 on the caging element 80 and the rib 85 on the sleeve due to the interengagement of pins 82 with the caging element 80 within the slots 8|. Likewise, under the same condition the inner spring 89 is confined under pressure between the spring seat 86 on the caging element 84 and rib 85 on sleeve 'l5 due to engagement between the snap ring 81 and said rib.

The end of the piston rod 58 extending beyond the pressure head 61 is pivotally connected by a pin 9| to a lever 92 intermediate its ends. A rod 83 is pvotally connected at one end by a pin 94 to one end of the lever 92 while the opposite end of ysaid rod is pivotally connected by a pin 95Vto the end of lever 52 outside of the control valve device 32. The opposite end of lever 92 is pivot- 4ally connected by a pin 96 to one end of a link 91 the opposite end of which is pivotally connected by pin to the end of the power piston rod 22. The link 91 provides for rocking of the lever 92 with respect to the pilot piston rod B8 and power piston rod 22, it being seen that both of said rods are rigidly held in parallel relation by pressure heads 6l' and 23, respectively.

The pressure chamber 62 at one side of the pilot piston 6l is connected by a pipe 98 to the manually operative selector valve device 6, while chamber '63 at the opposite side of said piston is connected by a pipe 99 to said device.

The selector device 6 located at the operators control station, as inthe pilot house of the ship and therefore remote from the pneumatic control motor I5, is provided for varying the pressure of liuid in either of the control pipes 98 or 99 while retaining the other of said pipes open to atmosphere. for controlling operation of motor i5 to move the maneuvering gear shaft I to its different positions.

The selector valve device 6 comprises a casing in which a, rockable shaft |00 is journaled. A lever |0I is secured to shaft |00 to turn same `and is movable to different positions indicated by legends in Fig. l, which positions it will 'be noted correspond in name to the positions ofthe maneuvering gear shaft I. Two cams |82 and |03 are secured to turn with the shaft |00, the cam |02 being provided to control the operation of two directional control or selector valve devices |04 and |05 which are operative in accordance with the direction of movement of lever l0| from its neutral position shown to selectively connect either pipe 98 or pipe 99 to a self-lapping valve device |06 and to open the other of said pines to atmosphere, the self-lapping valve device |05 being controlled by the cam |03,

The directional control valve devices |04 and |05 are located in the casing opposite each other and at opposite sides of the cam |02. Both of these devices may be of identical construction each comprising two oppositely seating poppet valve |01 and |08 contained in chambers |08 and l l0, respectively, and having axially aligned uted stems engaging each other in a chamber A spring |l2 in chamber |09 acts on the valve |01 for seating same and for at the same time un seating the valve |08. A plunger |l3 is slidably mounted in the casing.and has one end engaging cam |02 while the opposite end is disposed in chamber l l0. This plunger carries a pressure member H4 which engages the valve |08 and a spring ||5 acting on the pressure member for operating same to seat said valve and unseat the valve |01 upon movement of plunger l I3 in the direction of said valves. With the lever |0l and cam |02 in their neutral positions shown in Fig. 1, the plunger ll3 is permitted to move away from the valve |08 to provide for seating of valve |01 and unseating of valve |08 by spring |l2.

Initial movement of lever l0l in the direction of the left hand from a neutral position in which it is shown will actuate cam |02 and thereby the plunger ||3 of the valve device |04 in the direction of valve |08 for seating said valve and unseating the valve |81, this change in condition of the respective valves being obtained by the time the lever lill obtains the position indicated by the legend Stop and being then maintained in all positions of said lever beyond the Stop position. Movement of lever |0| in the direction of the right hand is adapted to seat valve |08 and unseat valve v|81 in the valve device |05 by the time the lever |0| obtains the Stop position at the right hand side of its neutral position and this condition of these valves is then adapted to be maintained in all positions of said lever beyond the Stop position. When the lever l0l is rocked toward the left hand for seating the valve |08 and unseating the valve |01 of the valve device l04, the cam |02 provides for the valve |08 in the valve device |05 remaining open and the y |05 is also connected to chamber |l1 by a passage |l8. Chamber in the valve device |04 is yconnected to vthe control pipe 99 leading to the pilot device 33 while the corresponding chamber in valve device |05 is connected to the control pipe 88 alsoleading to said pilot device. Chamber lll! in each of the valve devices |04 and |05 is open to the atmosphere through a passage l |9.

From the above description it will be seen that upon movement of lever 0l from its neutral position shown in the direction of the Vleft hand the valve device I 04 will connect control pipe 99 to chamber |I1 while the valve device |05 will open the control pipe 98 to the atmosphere. On the other hand if lever is rocked in the direction of the right hand from neutral position the valve device will connect the control pipe 98 to chamber while the valve device |04 will connect the control pipe 99 to the atmosphere.

The self-lapping valve device |06 is provided for supplying lluid under pressure to chamber ||1 and thereby to either pipe 98 or 99 as determined by the direction of movement of the control lever |0| and the consequent operation of the directional control valve devices |04 and |05.

The self-lapping valve device |06 comprises two spaced and axially aligned flexible diaphragms |22 and |23 which are rigidly clamped around their peripheries in the casing. Between these diaphragms is a chamber |24 which is constantly supplied with fluid under pressure from the supply pipe 39 through a suitable reducing valve device |25 and a pipe |26 leading to said chamber, said reducing valve device being operative to maintain the iluid at any desired pressure such as 100 pounds per square inch in the chamber |24. At the opposite side of the diaphragm |23 is a chamber |21 which is constantly open to the atmosphere through a passage |28 while at the opposite side of diaphragm |22 is a chamber |29 in constant communication through a port |30 with chamber ||1.

A stem |3| in chamber |24 has one end clamped to the diaphragm |23 while the opposite end is clamped to the diaphragm |22, the means clamping said stem to diaphragm |22 embodying a guide element |32 projecting through chamber |29 and slidably mounted in a bore in the lower end of a sleeve |33 which is secured in the casing in axial alignment with the two diaphragms |22 and |23 and directly below the operating shaft |00 and cam |03.

A poppet valve |34 is contained in a chamber |20 in the upper end of stem |3|, which chamber is constantly supplied with iluid under pressure from chamber |24 by way of passages |35 in the stem |3I. Chamber |20 also contains a spring |36 acting on the valve |34 for urging same upwardly toward a seat provided on the adjacent end of the guide element |32.

The valve |34 has a fluted stem extending through a suitable bore in the guide element |32 into a chamber |31 provided in sleeve |33. The chamber |31 is constantly open through one or more ports |38 in sleeve |33, to the chamber ||1 which encircles said sleeve. A release valve |39 in chamber |31 engages the end of the fluted stem of valve |34 and in turn has a fluted stem |40 mounted to slide in a bore in a plunger |4 I. The plunger |4| is mounted to slide in sleeve |33 and has suitable guide portions |42 slidably engaging the inner wall of sleeve 33. A ring shaped packing |43 disposed above the guide portions |42 is expanded into an annular groove provided in the inner wall of sleeve |33 and has sliding contact with the outer surface of plunger |4| for preventing leakage of fluid under pressure from chamber |31 along said plunger and out of the upper open end of sleeve |33. The bore in plunger |4| is open above the packing |43 to the atmosphere through one or more ports |44 and said bore contains a spring |45 acting on stem |40 of the release valve |39 urging said valve in a direction out of said bore and thus away from its seated or closed position against the end of said plunger.

An adjusting screw |46 is screw-threaded nl the upper end of plunger |4| and has a head |41 which engages the cam |03. A spring seat |48 is secured to the plunger |4| above the end of sleeve |45 and interposed between this seat and the casing is a bias spring |49 which is operative against the spring seat |48 with a force just sucient to urge the plunger |4| out of seating engagement with the release valve |39, as shown in the drawings.

In chamber |24 between the two flexible diaphragms |22 and |23 is a coil control spring |50 encircling the stem |3| and having one end supported on an annular ledge |5| in the casing while the opposite end acts against the diaphragm |22 for urging same in the direction of sleeve |33. This spring is adapted to be fully expanded with the parts in the position shown in Fig. l, assumed when the lever |0| is in its neutral position shown. and to oppose all movement of the diaphragms in a downwardly direction from this position. The two diaphragms |22 and |23 are of equal areas so that the pressure of fluid in chamber |24 acting on the diaphragm |22 is opposed and balanced by said fluid pressure acting on the diaphragm |23. Thus spring |50 provides the only force for opposing movement of the diaphragms in a downwardly direction.

Operation With the lever |0| of the selector valve device in its neutral position shown, the spring |49 acting on seat |48 will urge plunger |4| to the position shown in which said plunger is pulled away from the release valve |39 due to the action of spring |45 on said valve and also to the fact that the control spring |50 is expanded to its free height thus removing the force on said valve tending to urge same in an upwardly direction. Under this condition the spring |38` will hold the supply valve |34 in contact with its seat and chambers ||1 and |29 will both be open to the atmosphere through ports |38, past the release valve |39 and thence through the bore in plunger |4| and ports |44.

With the selector lever |0| in its neutral position the directional control valve devices |04 and |05 will both occupy the positions shown in which the Valves |08 are unseated so that both control pipes 98 and 99 and thereby chambers 62 and 63 at opposite sides of piston 6| inthe pilot device 33 will be open to the atmosphere.

With the opposite sides of the pilot piston 6| thus subject to atmospheric pressure said piston will be held in its neutral position shown by sleeve 15 engaging one side of the piston and the washer 11 engaging nut 1| on the end of the piston rod sleeve 10 under the force of spring 18 holding collar 16 on said sleeve in contact with shoulder 12 in the casing and holding the washer '|1 in contact with shoulder 13 on the pressure head 14. With the pilot piston 6| in its neutral position all parts of the pneumatic control motor I5 will occupy the neutral positions shown in Fig. 2 for reasons which will be apparent from the description to follow, and accordingly, the gear sector and" sprocket wheels 1 and 4 will occupy their neutral positions shown for correspondingly positioning the maneuvering gear shaft I.

Let it be assumed, as just mentioned, that the lever |0| is initially in its neutral position shown under which condition the engine on the craft will be stopped, and that it is desired to cause operation of said engine to move the craft forwardly. To accomplish this end the operator moves the lever |0| from its neutral position in a counter-clockwise direction, or in a direction indicated by the arrow bearing the legend Aheadj to the position indicated by the legend Start The initial movement of lever out of neutral position actuates the cam |02 to reverse the valves of the directional control valve device |04 t0 `thereby place the control pipe 99 in communication through passage HS with chamber while the directional control valve device |05 remains in the condition shown opening the control pipe `98 to the atmosphere.

As the lever lill is thus moved -to Start position the cam |03 initially operates through the adjusting screw |46 to move the plunger |4| into contact with the release valve |39 and to then move said valve along with said plunger to unseat the valve |34. The cam |03 is so designed that the supply valve |34 will thus be unseated before the lever |0| obtains the stop position.

With the valve |34 unseated as just described fluid under pressure will flow from chamber |24 between the diaphragme past said valve to chamber |31 within sleeve |33 and then through passages |3B to chamber and from chamber Il? through passage H6 and past valve |61 in the directional control valve device |34 to pipe Sil leading to chambel` 63 at one side of the pilot piston in the control motor |5. At the same time as fluid under pressure is thus supplied to chamber H1, it also flows through port |50 to chamber |29 at the top of diaphragm |22 and acts on said diaphragm to deflect same in a downwardly direction against spring |50 thus tending to pull the guide element |32 into seating engagement with the supply valve |34. Such seating of valve |34 may be provided for by the time the pressure of uid in chamber |29 and thus in the control pipe 99 is built up to a chosen degree such as seventy-five pounds, or if desired,` the cam |93 may be so designed as to maintain valve |36 open with the lever lill in Start position so that uid at the relatively high pressure, of for instance one-hundred pounds, supplied by the reducing valve device may be obtained in the control pipe 99.

Fluid at this high pressure obtained in pipe 99 flows to chamber 63 at the left hand side of the pilot piston 6| and acts thereon to move said piston to an extreme right hand position` dened by contact between the washer and the left hand end of sleeve l5. As the piston 6| thus moves it will be seen that the initial portion ol its movement is opposed-only by the spring t3 following which the washer 'il will engage the adjacent end of caging element 80 and thenl move same relative to the sleeve 75 so that continued c movement of the piston will bey opposed by both springs 18 and 89. After a certain degree of this continued movement the washer 'i8 will engage the end of the caging element 84, so that further movement of the piston to its extreme right hand position will then be opposed by all of the springs 18, 89 and B8.

The power piston l1 has a greater resistance to movement than lever 52 and the valve mechanisms 35 or 36 in the control device 32, as a result of which movement of the pilot piston El in the direction of the right hand will rock the lever 92 about its fulcrum connection with the power piston rod 22 to thereby pull the operating rod 93 in the direction of the right hand. This movement of the operating rod 53 in turn rocks the control lever 52 in the control device 32 in a corresponding or clockwise direction to thereby actuate the valve device 35 to supply uid under pressure to chamber |8 and at the same time to actuate the valve device 36 to release luid under `pressure from chamber 20 for thereby establishing a differential of fluid pressures on the power piston Il for moving same in the direction of the right hand to operate the gear sector and sprocket wheels l and 4 to turn the maneuvering gear shaft in a clockwise direction and thus in the direction of the arrow indicated by the legend Ahead which corresponds to the direction of movement of the lever |0|.

vAs the power piston Il is moved in the direction of the right hand it carries with it the lower end of the equalizing lever 92, and after the pilot piston 6| obtains its extreme right hand position above described, said lever is rocked by the power piston I1 in a counterclockwise direction about its fulcrum .connection with the pilot piston rod 68 and thus actuates the rod 93 to turn the lever 52 in a .eounterclockwise direction back toward its neutral position which will be obtained when the power piston obtains a position in which the maneuvering gear shaft is in Start position. When the lever 52 is returned to its neutral position as just mentioned, the valve devices 35 and 3B are conditioned as above described to I equalize the fluid pressures on the opposite sides of the power piston I1 due to which movement of said piston will stop in a position determined by the position of the pilot piston and hence in accordance with the selected position of the selector lever il When the pilot piston 6| is moved its full stroke as just described the corresponding movement Yof the power piston Il will operate the gear sector and thereby the sprocket wheel and connected sprocket wheel 4 to turn the maneuvering gear shaft to its Start position in which the engine will be started or placed in motion in a. direction for propelling the craft forwardly. n

It will now be seen that movement of the operating lever |0| in the direction indicated by the legend Ahead in Fig. 1 and to the position indicated by the legend Start at the left hand side of the device will cause movement of the maneuvering control shaft in the direction indicated by the legend Ahead and to the position indicated by the legend Start, the direction of movement of and the position obtained for vmaneuvering .shaft l therefore corresponding to the direction of movement and position of the operating lever |0| of the selector device |05.

After the engine has been put in motion for causing forward movement of the craft, the lever lill will be returned from the Start position to thek adjacent position indicated by the legend Full or to any other desired speed position intermediate said Full and the next adjacent position indicated by the legend Slow. As the lever |0| is thus moved from Start position in a clockwise direction, the cam |03 permits spring |49 'acting on the plunger |43 to move said plunger upwardly and away from the exhaust valve |39, said valve being held against movement at this time by the pressure of spring and due to the fact that the pressure of fluid in chamber |29 above the diaphragm |22 equals at least the .opposing control force of spring |50.

When the valve |39 is thus unseated fluid under pressure will be released from the pilot piston chamber 63 through pipe 90 and the directional control valve device |04 to chamber and thence past the release valve |39 to the atmosphere. As the pressure in the pilot piston chamber 63 is thus reduced a corresponding reduction in pressure occurs in chamber |29 above the diaphragm |22 which permits spring |50 to urge said diaphragm and thereby the release valve |39 in an upwardly direction toward plunger I4I and said valve will become seated against said plunger to limit the reduction in pressure in the pilot piston chamber 63 in a position of said plunger determined by the position of cam |03 and of lever IGI. If the lever IDI is merely moved to the Full position the exhaust valve |39 will become seated when the pressure acting on the pilot piston 63 and thereby in chamber |29 on diaphragm |22 becomes reduced to a certain pressure, such as for instance fty-two pounds. If, however, the lever I 9| is moved to the Slow position the spring |49 acting on the plunger I4I will be permitted to raise said plunger to a position where the pressure acting on the pilot piston 63 and in chamber |29 above the diaphragm |22 will become reduced to a pressure such as seventeen pounds. Intermediate positions of the plunger I4I obtained in different positions of lever IUI between the Full and Slow positions will provide for seating of the exhaust valve |39 when the pressure in chamber |29 above the diaphragm and thus in chamber 63 at one side of the pilot piston becomes reduced to corresponding intermediate pressures, between the fifty-two and seventeen pounds pressures ob.- tained in the Full and Slow positions, respectively.

When the pressure of iluid in chamber 63 at the left hand side of the pilot piston 8| is reduced -by return of lever IDI from Start position to either the Full or Slow positions or an intermediate position, the combined force of srings 18, 88 and 89 on the washer 11 overbalances the pressure of iluid on the pilot piston 6I and pulls said piston in the direction of the left hand until at the time the pressure of such iluid becomes reduced to the high limit of fifty-two pounds above mentioned, the snap ring 81 on the caging element 84 will have contacted the rib 85 of sleeve 15 and thus removed the force of spring 89 from the washer 11. If the pressure of fluid in chamber 63 at one side of the pilot piston is further reduced said piston will be moved under the action of springs 88 and 18 until at the time such pressure is reduced to the seventeen pounds above mentioned, the pressure of spring 88 will have been removed from washer 11 due to the caging element 80 engaging pins 82 in sleeve 15.-

As above mentioned the springs 88 and 89 are assembled in the pilot device under a certain degree of precompression, such as for instance of a degree equivalent to five pounds uid pressure on the pilot piston 6I. The seventeen and iifty-two pounds pressures supplied by the selector device in the Slow and Full positions is approximately two and one-half pounds less than required to move the pilot piston 6I against the springs B8 and 89, respectively, and therefore substantially midway between the pressures required to move said piston into contact with the cages 8D and 84 and to then move said cages. A variation from the seventeen and nity-two pounds, either above or below these values, of for instance two pounds will therefore have no effect upon the exactness of positioning of the pilot piston with the selector in either Full or Slow position.

From the above description it will now be seen that with the lever IIII in the Full speed position at the left hand side of its neutral position the washer 11 will be just in engagement with spring seat 88 on the caging element 84, but the spring 89 acting on said seat will be ineffective on the pilot piston 8|, while when the lever IUI is in the Slow position the washer 11 will be just in contact with spring seat 83 on the caging element and the spring 88 will be ineffective on said piston. For all intermediate positions of lever IUI the washer 11 will assume a position opposed and determined by both springs 18 and 88, but unopposed by spring 89 acting on the caging element 84.

Let it be assumed that lever I 0I has been returned from Start position to Full position as a result of which the pilot piston 6I will be moved by springs 18 and 88 to a position n which the washer 11 is just in contact with spring seat 86 on the caging element 84 with the snap ring 81 in contact with rib 85 of the sleeve 15. This movement of the pilot piston BI acts to turn the lever 92 in a counterclockwise direction about the fulcrum connection with the power piston rod 22 to cause a corresponding rocking movement of the control lever 5.2 of the control device 32 for thereby actuating the valve device 36 to supply iiuid under pressure to chamber` I8 at the left hand face of the power piston I1 and for at the same time effecting operation of the valve device 35 to release iluid under pressure from chamber 28 at the opposite side of the power piston. A differential of fluid pressures will thereby be created on the power piston to move same in the direction of the left hand. After the pilot piston 6I comes to rest in the position in which the force of spring 88 is just removed from the washer 11, movement of the power piston I1 in the directon of the left hand will rock the lever 92 about the fulcrum connection with the pilot piston rod 68 and thereby operate rod 93 to turn lever 52 back to its neutral position for equalizing the fluid pressures on the power piston so as to stop said piston in a position corresponding to the position of the pilot piston 6I and the Full position of lever IUI.

As the power piston I1 is thus moved from its iextreme right hand position toward the left hand it operates the gear sector II to turn the sprocketI wheels 1 and 4 and thereby the maneuvering gear shaft I from its Start position in a counter-clockwise direction and this movement will cease when said shaft obtains its Full position since opposing fluid pressures on the power piston I1 will be equalized at this time.

Now let it be assumed that the lever IDI is returned from Full position to Slow position to thereby reduce the pressure of fluid in chamber 63 at the left hand face of the pilot piston 6I to the low degree of seventeen pounds above mentioned. The force of springs 18 and 88 on washer 'I1 in the pilot device will then move the piston 6I further toward the left hand to a. position in which the caging element 80 just comes into contact with the pins 82 in which position it will stop as required by the position of lever I 0 I. This movement of the pilot piston 6I will again operate the lever 92 and thereby the control device 32 to again supply fluid under pressure to chamber 2U at the right hand face of the power piston I1 and reduce the pressure of iluid on the opposite face for causing movement of the piston further in the direction of the left hand and this movement will continue until the control lever 52 is again returned to neutral position for equalizing the uid pressures on the power piston, which will occur in a position of said piston corresponding to the position in which the pilot piston 6I was stopped. This further movement of the power piston I 1 toward the left hand will eiect a corresponding operation of the gear sector II and sprocket wheels 1 and 4 to turn the maneuvering gear shaft I to its Slow position in which it will be stopped due to the power piston I1 being stopped and it should be noted that this position corresponds to that called for by the position of lever IUI.

It will be readily seen that if the control lever IOI is moved to any position intermediate Full and Slow the proportional pressure provided in chamber 63 on the pilot piston GI will provide a corresponding positioning of said piston against the combined opposing forces of springs 18 and 88, and that the valve device 32 and power piston I1 will respond to adjust the maneuvering gear shaft I to a corresponding position between Full and Slow positions. Thus by operation of lever !I in the Zone between Full and Slow positions to vary the pressure of iiuid in chamber G3 on the pilot piston SI between limits such as the fty-two and seventeen poundsv above mentioned, the pilot piston 6I will be positioned to provide for corresponding positioning of the power piston I1 and of the maneuvering gear shaft I to vary the speed or power output of the engine being controlled.

If now the operator desires to stop the engine, he moves the lever IDI to the position indicated by the legend Stop and the cam ID3 is so designed Y that in this position a further reduction in Huid pressure, to a chosen low degree such as ten pounds, will be effected in pipe 99 and pilot piston chamber G3 by operation of the self-lapping control valve device |06, as a result of which the spring 18, now alone effective on washer 11, will move said washer to a position intermediate the spring seat 83 on the caging element 80 and the shoulder 13 to thereby correspondingly position the pilot piston 6I for effecting operation of the power piston I1 in the same manner as above described to actuate the gear sector II and sprocket wheels 'I and 4 to return the maneuvering gear shaft I to its Stop position for stopping the respective engine. This position is not critical like the Slow and Full" positions above described so that positive position defining means is not required for same.

After the engine is stopped the lever IUI may be returned to its neutral position in which the self-lapping valve device |06 opens' chamber II 1 to the atmosphere and the cam |02 provides for operation of the directional control device |04 to open pipe 99 and pilot piston chamber 63 to atmosphere. The opposite faces of the pilot piston 6I' will then both be subject to atmospheric pressure so that the pressure of spring 18 on the washer 11 will move same into contact with shoulder 13 on the cover 14 and thereby return the pilot piston 6I to its neutral position. This movement of the pilot piston 6I will operate the lever 92 and thereby the control valve device 32 in the same manner as before described to cause movement of the power piston I1 back to its neuright hand side of the selector device lE. This operation of lever IUI actuates the selector valve device I to connect the control pipe 98 to chamber II1 and also operates the self-lapping valve device M6 in the same manner as before described ior supplying fluid under pressure to the pipe 98 and thence to chamber 62 at the right hand side of the pilot piston 6I. At this time chamber 63 at the left hand side of the pilot piston is open to the atmosphere by way of pipe t9 and the selector valve device I 04.

The pressure of fluid thus supplied to chamber 62 at the right hand side of the pilot piston moves said piston in the direction of the left hand to a position in which the left hand end of sleeve 15 engages the washer 11, the spring 18 opposing such movement throughout the full stroke of the piston BI and the springs 88 and 89 becoming successively effective to oppose such movement upon eng-agement of spring seat 83 on the caging element 8o with the washer 11 and subsequent engagement of spring seat 86 on the caging element 84 with said washer.

Thisl movement of the pilot piston operates the lever 92 and thereby thecontrol device 32 to supply fluid under pressure to chamber 20v and to release fluid under pressure from chamber I8 at opposite sides of the Power piston I1 for thereby moving said piston to its extreme left hand position in which uid pressures in said chambers will be again equalized by operation ofthe control valve device 32, this operation of the control device 32 and power piston I1 being substantially like that before described, as will be seen. This movment of the power piston I1 in turn operates the gear sector II and sprocket wheels 1 and 4 to turn the maneuvering gear shaft I in a clockwise direction from its Neutral position to the position indicated by the legend Start at the left hand side oi the vertical center line of gear 4. The engine will therefore be started in the direction to cause astern movement of the craft.

After the engine is thus put in motion, the lever IDI is returned toy either Full or Slow" position, or to an intermediate position at the right hand side of said lever for thereby reducing the pressure of iiuid acting on the right hand side of the pilot piston El, as a result of which said piston will be moved toward the right to a position depending upon the reduced pressure of fluid in chamber 62. For instance ii the lever is in Full position the pilot piston will assume a position where the snap ring 81 in the caging element 84' will be in contact with rib 85 in sleeve 15 while spring seat 85 at the opposite end of said caging element will be just in contact with washer 11. If the' lever is moved to the Slow position, the piston El will assume a position in which the caging element 8B will be in contact with pins 82 in the sleeve 15 and also in contact with the washer 11. For all intermediate positions of lever [0I the caging element will be disengaged from the pins 82 but in contact with the washer 18. Thus the position of' the pilot piston 6I, for all positions of the lever IUI between Full and Slow positions at the right hand side of the neutral position, is determined by the combined action of springs 88 and 18 and the opposing pressure of iiuid supplied by the selector valve device 6, the same as above described for movement of the craft forwardly.

It will be seen that when the lever IUI is moved in the direction of the left hand to cause Imove ment of the craft Ahead the sleeve l in the pilot device remains stationary and the washer 'l1 moves with the pilot piston 6|, while upon movement of the lever ||l| in the direction of the right hand for causing Astern movement of the craft the washer 'Il remains stationary while the sleeve 'I5 is moved with the piston 6| In both cases however the spring I8 opposes all movement of the pilot piston from neutral position while the springs 68 and 89 are successively rendered effective upon an increase in pressure on the pilot piston or ineective upon a reduction in pressure on the pilot piston, in the same order and to accomplish the same results for both directions of movement of levei` ||l| and thereby of the pilot piston 6|.

When the pilot piston 6| moves from its neutral position toward the left hand to a position corresponding to the position of the control lever IDI at the right hand side of its neutral position between Slow and Full positions, the lever 92 and control valve device 32 will be operated to cause a corresponding positioning of the power piston and thereby of the gear sector sprocket wheels and 4 and maneuvering gear shaft I, in the same manner as before described as will be readily seen.

If during Astern movement of the craft the operator desires to stop the engine, he moves the lever |0| to the Stop position at the right hand side of the neutral position to thereby reduce the pressure in the control pipe 98 for positioning the pilot piston 6I to cause a corresponding positioning of power piston I'I and thereby of the maneuvering gear shaft required for stopping of the engine. After the engine is stopped, the operator may then move the lever |6| back to its neutral position for completely releasing fluid under pressure from the pipe 98 by way of the selector valve device |65 and thereby from chamber 62 at the right hand face of the pilot piston 6|. The pilot piston 6| will then be returned to its neutral position by spring 'IS following which the power piston I'l will be operated to its Yneutral position for returning the maneuvering gear shaft to its Neutral position. Y

If the craft is being propelled in a forwardly direction and the operator desires to reverse the direction of movement, he may do so by moving the lever |6| from whatever position it may occupy at the left hand side of neutral position to the Start position at the right hand side of neutral position for thereby opening the control pipe S9 to atmosphere and for supplying fluid under pressure to pipe 68 to the degree required for moving the pilot piston 6| to its extreme left hand position upon the release of iiuid under pressure on the opposite side of the pilot piston by way of pipe 99. After the pilot piston 6| thus operates and a corresponding operation of the power piston I1 and movement of the maneuvering control shaft I to its Start position at the left hand side of the vertical centerline of said shaft occurs, the operator may move the lever |6|, back to Full, Slow or any desired intermediate speed position at the right hand side of the neutral position for causing movement of the craft in an astern direction at a desired rate of speed;

In case the craft is moving in an astern direction and the operator desires to reverse the direction of movement, he will merely move lever ||l| from the position it may occupy at the right side of its neutral position to the "Start` position at the opposite side of the neutral po- A sition and then back into a 'selectedposition in the zone between Full and- Slow positions following which the control motor I5 will operate to correspondingly `position the maneuvering gear shaft I in a manner which will be evident from the above description.

In order that the pilot of the craft may be aware of the integrity or proper operation of the control system I associate with the control valve device 32 two switches |57 and |58, one located at one side of the lever 52 for operation thereby upon movement in one direction and the other located at the opposite side of the lever for operation by the lever upon movement in the opposite direction. Each of these switches may be of identical structure comprising, diagrammatically, a contact element |66 arranged to be operated by lever 52 upon movement out of its neutral position t6 electrically connect two fixed contacts |6| and |62. A spring |63 acting on each of the contact elements |66 is provided for actuating the element out of bridging relation with the contacts ISI and |62 when the lever |52 is returned to its neutral position. The contact |6| of both switches |51 and |68 is connected to any suitable source of electrical current such as a battery |64, while the contact |62 of both switches is connectedto a wire |65 leading to an indicating device |66, preferablyof the audible type, such as a buzzer. By this arrangement it will be seen that rocking of the lever 52 in either direction in response to movement of the lever |0| out of its neutral position will cause operation of the buzzer |66 to indicate to the pilot that the pilot device 33 and control device 32 associated therewith are operating as intended. When the power piston l1 then moves to the position determined by the position of the pilot piston 6I and the lever 52 is returned to neutral position, the circuit to the buzzer |66 will be opened and said buzzer will stop sounding to indicate to the pilot that the power piston Il has operated as intended and therefore the maneuvering gear shaft has been moved to the desired position. It will be seen that if the apparatus operates as intended in response to movement of the control lever |0| in either direction, the buzzer |66 will be caused to operate and then stop operating. In case the 1 buzzer |66 fails to operate at all, the pilots attention Awill be directed to the fact that the pilot device 33 or control Ydevice 32 is not operating as required or that some other part of the system is out of order, such for example as the circuit to the buzzer or possibly failure of the fluid pres- Vcally controlled switch device |61 controlled by the pressure of fluid supplied by the reduclnsl valve device 46 to pipe 4|. 'Ihe opposite side of piston |68 is subject to the pressure of a spring |1|, which is of such value as to provide for movementl of the piston |68 to the position shown if the pressure in pipe 4| is above a chosen safe degree, but to move piston |68 in the direction of chamber |69 in case the pressure in pipe 4| is at a lower degree.

The piston |68 is connected by a stem |12 to a movable switch contact |13 which is arranged to electrically connect two fixed contacts |14 and |15 upon movement of the piston |68 to its lower position and to open the circuit between such contacts when in its upper position shown. The contact |15 is connected to the battery |64 while the contact |14 is connected to wire |65 leading to the buzzer |66. By this arrangement, the contact |13 will be held out of engagement with contacts |14 and |15 whenever the pressure of iuid supplied by the reducing valve device 40 to pipe 4| is at or above a safe degree, but in case this pressure becomes reduced to below the safe degree, movement of the piston |68 to its lower position will move contact |13 into engagement with the contacts |14 and |15 for connecting the battery |64 to the buzzer |66 to cause operation of said buzzer and thereby call the pilots attention to the low pressure condition in the system. A cutout switch |16 is provided in wire |65 to render the buzzer |66 inoperative when the system is void of uid under pressure.

S ummary From the above description, it will now be seen that I have provided a system whereby a member may with exactness be caused to move to any selected one of a plurality of different positions selected by an operator at a remote control station. At the control station, the operator is provided with a selector device having positions corresponding to those of the member to be controlled, and associated with said member is a pneumatic power mechanism arranged to operate in accordance with selected operations of the pilots selector device to cause positioning of said member in accordance with a chosen operation of the selector device. I associate with the power means a plurality of springs arranged to become successively effective or to be rendered successively ineffective to provide for accurate positioning of the pilot means in response to operation of the selector device in order that the power means which controls the member being operated may with accuracy move said member to the selected position. In order to insure that the operator will be alwaysiaware of the operative condition of the system and thus minimize the possibility of failure of the system in use, I provide means for indicating whether or not the pressure of fluid in the system is adequate and for also indicating whether the mechanism operates as intended in response to a selected operation of the operator.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

In combination, a cylinder, a power piston in said cylinder, a valve device comprising a lever` means operable upon movement from one position to a second position to create a differential between uid pressures acting on opposite sides lof said piston for eiecting movement thereof and operable upon return to said one position to destroy said diierential to stop movement of said piston, another cylinder, a pilot piston in the last' named cylinder movable by iiuid pressure, means connecting the two pistons and lever means, said pilot piston being operable upon movement by iiuid under pressure to actuate said means to move said lever means to said second position and said power piston being operable upon cessation of movement of said pilot piston to actuate said means to move said lever means to said first position, a manual control device at a control station operable by an operator to eiect a supply of uid under pressure to actuate said pilot piston, a signal device at said control station, and means for effecting operation of said signal device controlled by said lever means and operable upon movement of said lever means out of said one position to eiect operation of said signal device and to stop operation of said signal device upon return to said one position.

ROY R. STEVENS. 

